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Scandinavia is generally considered to have been covered extensively with ice throughout marine isotope stages (MIS) 4-2 between 75 and 10 ka. Here we present evidence for ice-free, warm conditions in the central area of the Scandinavian glaciations during MIS 3. Our multiproxy data obtained from a lacustrine sequence in northern Finland reveal not only significant response in the northeastern sector of the Scandinavian Ice Sheet to warming during the early part of MIS 3, but also indicate rapid climate warming to present-day temperatures in this ice-free period. New climate-model simulations for interstadial conditions in MIS 3 confirm the high mean July temperatures northeast of the Scandinavian Ice Sheet in response to the high insolation values and the presence of the ice sheet during MIS 3. Keywords: climate variability, MIS 3, Scandinavia, multiproxy, climate modeling. doi: 10.1130/G23995A.1

Byline: Eugene R. Wahl (1), Caspar M. Ammann (2) Abstract: The Mann et al. (1998) Northern Hemisphere annual temperature reconstruction over 1400--1980 is examined in light of recent criticisms concerning the nature and processing of included climate proxy data. A systematic sequence of analyses is presented that examine issues concerning the proxy evidence, utilizing both indirect analyses via exclusion of proxies and processing steps subject to criticism, and direct analyses of principal component (PC) processing methods in question. Altogether new reconstructions over 1400--1980 are developed in both the indirect and direct analyses, which demonstrate that the Mann et al. reconstruction is robust against the proxy-based criticisms addressed. In particular, reconstructed hemispheric temperatures are demonstrated to be largely unaffected by the use or non-use of PCs to summarize proxy evidence from the data-rich North American region. When proxy PCs are employed, neither the time period used to 'center' the data before PC calculation nor the way the PC calculations are performed significantly affects the results, as long as the full extent of the climate information actually in the proxy data is represented by the PC time series. Clear convergence of the resulting climate reconstructions is a strong indicator for achieving this criterion. Also, recent 'corrections' to the Mann et al. reconstruction that suggest 15th century temperatures could have been as high as those of the late-20th century are shown to be without statistical and climatological merit. Our examination does suggest that a slight modification to the original Mann et al. reconstruction is justifiable for the first half of the 15th century ([proportional to]+0.05.sup.a), which leaves entirely unaltered the primary conclusion of Mann et al. (as well as many other reconstructions) that both the 20th century upward trend and high late-20th century hemispheric surface temperatures are anomalous over at least the last 600 years. Our results are also used to evaluate the separate criticism of reduced amplitude in the Mann et al. reconstructions over significant portions of 1400--1900, in relation to some other climate reconstructions and model-based examinations. We find that, from the perspective of the proxy data themselves, such losses probably exist, but they may be smaller than those reported in other recent work. Author Affiliation: (1) Environmental Studies and Geology Division, Alfred University, One Saxon Dr., Alfred, NY, 14802, USA (2) Climate and Global Dynamics Division, National Center for Atmospheric Research Boulder, Boulder, Colorado, U.S.A. Article History: Registration Date: 15/03/2006 Accepted Date: 01/03/2006 Online Date: 31/08/2007 Article note: The National Center for Atmospheric Research is sponsored by the National Science Foundation, USA. The authors contributed equally to the development of the research presented.

Satellite remote sensing offers a convenient way to monitor changes in the thermal budgets of Earth's subaerially active volcanoes. By using data acquired by the National Aeronautics and Space Administration's Moderate Resolution Imaging Spectro-radiometer, we have calculated the amount of heat released into the atmosphere by 45 volcanoes active during 2001 and 2002, in order to quantify the contribution active volcanism makes to Earth's energy budget. We report that the amount of heat radiated into the troposphere by these volcanoes, as detected from space, was ~5.34 x [10.sup.16] and 5.30 x [10.sup.16] J/yr during 2001 and 2002, respectively. This energy flux is three orders of magnitude less than the amount of energy consumed by the United States of America for residential, manufacturing, and transportation purposes during 1999. Keywords: volcanoes, remote sensing, thermal emission, mass balance.

The Southern Great Plains 1999 (SGP99) Experiment, conducted in Oklahoma, July 8-21, 1999, provided an opportunity to observe spatial and temporal variations in surface temperature. During the experiment, aircraft (Passive/Active L/S-band airborne sensor) and satellite [Advanced Very High Resolution Radiometer (AVHRR) and TIROS Operational Vertical Sounder (TOVS)] sensors collected surface temperature that was compared to in situ observations over the same time period to determine the accuracy and consistency of surface temperature measurements at different spatial resolutions using remotely sensed data. In addition, in situ surface temperature was observed in a 400 x 400 m field at various spatial grid spacing: 50 m, 10 m, and 1 m in order to quantify the variability of the spatially distributed behavior of surface temperature during a drydown period. Average differences between the in situ surface temperature observations and the aircraft and satellite sensors utilized during this study ranged from 0.7 [degrees]C (AVHRR High Resolution Picture Transmission) to more than 20 [degrees]C (AVHRR Global Area Coverage (GAC), TOVS). We have shown that the temporal adjustments of the remotely sensed surface temperatures (from aircraft and satellite sensors) shows a better comparison to in situ ground data. A ratio was set up using information derived from a mosaic land surface model to temporally locate the various estimates of surface temperature. The corrected surface temperature comparisons decreased the average differences (with in situ) to as much as 78% [AVHRR (GAC)] and as little as 6% (TOVS). The average difference between remotely sensed and in situ observations was around 48%. Index Terms--Satellite remote sensing, scaling, surface temperature, validation.

A riparian corridor along the Rio Grande dominated by the Eurasian tamarisk or salt cedar (Tamarix spp.) is being studied to determine water and energy exchange rates using eddy covariance instrumentation mounted on a 12-m tower. The potential of using remotely sensed data to extrapolate these local estimates of the heat fluxes to large sections of the Rio Grande basin is under investigation. In particular, remotely sensed (radiometric) surface temperature can be used to estimate partitioning of net radiation energy into sensible and latent heat fluxes from vegetated landscapes. An important issue that has not been addressed adequately in the application of radiometric surface temperature data is the effect of using different time-averaged quantities in heat transfer formulations. This study evaluates the impact on sensible heat flux estimation of using relatively short time-averaged (1 min) canopy temperatures measured from a fixed-head infrared radiometer with 1-, 10-, and 30-min time-averaged micrometeorological input data used in estimating the resistance to heat transfer. The results indicate that, with short time-averaged radiometric surface temperatures (essentially 'instantaneous' from a satellite), variations in sensible heat flux strongly correlate to fluctuations in net radiation conditions. Under near-constant net radiation input, natural perturbations in surface temperature also contribute to variations in sensible heat flux but are typically an order of magnitude smaller. The resulting implications for computed heat flux estimates using data from remotely sensing platforms and validation with flux tower measurements along riparian corridors are discussed.

Research presented concerns the dynamics of fluid inclusions, fluid immiscibility, and the use of geothermobarometers in geochemistry. Hydrothermal fluid dynamics are studied and a technique for retrieving crystal growth temperatures is detailed.

A technique is presented to separate uncontaminated land and sea brightness temperatures from mixed coastal pixels in 37-GHz vertically polarized passive microwave data from the Special Sensor Microwave Imager (SSM/I) instrument. Combining a mathematical model of the instrument response over several neighboring footprints with a GIS representation of the coastline yields a relationship between land and sea brightness temperatures and radiation measurements made at the satellite. Inverting this relationship allows separate land and sea brightness temperature values to be derived for each mixed coastal pixel in the original image. The technique has been successfully applied to 37-GHz vertically polarized SSM/I imagery for test areas covering the Gulf of Aden and the British Isles. Errors in the retrieved brightness temperatures were estimated to be of the order of 1-2 K. Index Terms - Coastal zones, mixed pixels, passive microwave, Special Sensor Microwave Imager (SSM/I).

The worldwide network of in situ land surface temperatures archived in near-real time at the National Climatic Data Center (NCDC) has limited applications, since many areas are poorly represented or provide no observations. Satellite measurements offer a possible way to fill in the data voids and obtain a complete map of surface temperature over the entire globe. A method has been developed to calculate near-surface temperature using measurements from the Special Sensor Microwave/Imager (SSM/I). To accomplish this, the authors identify numerous surface types and make dynamic adjustments for variations in emissivity. Training datasets were used to define the relationship between the seven SSM/I channels and the near-surface temperature. For instance, liquid water on the surface reduces emissivity; therefore, the authors developed an adjustment to correct for this reduction. Other surface types (e.g., snow, ice, and deserts) as well as precipitation are identified, and numerous adjustments and/or filters were developed for these features. The article presents the results obtained from training datasets, as well as an independent case study, containing extreme conditions for deriving temperature from the SSM/I. The U.S. networks of first-order and cooperative stations, quality controlled by NCDC, serve as validation data. The correlation between satellite-derived and in situ temperatures during the independent case ('Blizzard of 1996') was greater than 0.95, and the standard error was 2 [degrees] C. The authors also present SSM/I-derived snow cover and wetness maps from this 2-week period of the blizzard. A prototype for blending the satellite and in situ measurements into a single land surface temperature product is also presented.

Measurements of the scattering cross section of a number of bare soils have been made with C[O.sub.2] laser illumination at 10.59 [[micro]meter]. The primary focus was on absolute calibration of the measurements. First, comparison of emissivity values resulting from the application of Kirchhoff's relation after angular integration of the bidirectional measurements, with emissivity values obtained from the analysis of the emitted radiation show excellent agreement to within less than 0.3%. Second, it was found that a simple formula holds for a relationship between the emissivity and co- and cross-polarized backscattering cross section at an angle of 30[degrees]. Third, a clear correlation was observed between emissivity and composition (in this case % Al + Fe oxides; % Si[O.sub.2]) for a homogeneous series of samples from the same area in Niger. These results emphasize the importance of calibrated experimental data. The implications of the research give evidence of the advantage of obtaining emissivity from remote reflectivity measurements and possibly only backscattering measurements, and remotely estimating mineral composition.

We propose a generalized split-window method for retrieving land-surface temperature (LST) from AVHRR and MODIS data. Accurate radiative transfer simulations show that the coefficients in the split-window algorithm for LST must vary with the viewing angle, if we are to achieve a LST accuracy of about 1 K for the whole scan swath range ([+ or -]55[degrees] from nadir) and for the ranges of surface temperature and atmospheric conditions over land, which are much wider than those over oceans. We obtain these coefficients from regression analysis of radiative transfer simulations, and we analyze sensitivity and error over wide ranges of surface temperature and emissivity and atmospheric water vapor abundance and temperature. Simulations show that when atmospheric water vapor increases and viewing angle is larger than 45[degrees], it is necessary to optimize the split-window method by separating the ranges of the atmospheric water vapor, lower boundary temperature, and the surface temperature into tractable subranges. The atmospheric lower boundary temperature and (vertical) column water vapor values retrieved from HIRS/2 or MODIS atmospheric sounding channels can be used to determine the range for the optimum coefficients of the split-window method. This new algorithm not only retrieves land-surface temperature more accurately, but is also less sensitive to uncertainty in emissivity and to instrument quantization error.

Bipolarized microwave brightness temperatures of Sahel semiarid landscapes are analyzed at two frequencies: 5.05 and 36.5 GHz. These measurements were performed in Niger, West Africa, by the radiometer PORTOS in the framework of the Hydrologic Atmospheric Pilot Experiment in the Sahel (HAPEX-Sahel), during the end of the rainy season (August-September 1992). The airborne microwave data were collected simultaneously with radiosoundings of the atmosphere, and ground measurements of surface temperature, soil moisture, and biomass of several vegetation types. After estimating the soil roughness parameters, it is shown that two kinds of vegetation canopies must be considered: sparse canopies and patchy canopies including bare soil strips. The mixed soil vegetation microwave emission is analyzed using a random continuous approach. The sparse canopy emission is efficiently described by considering the vegetation layer as homogeneous. Conversely, a simple soil-vegetation mixing equation must be used for the patchy canopies. The problem with retrieving the canopy temperature and the near-surface soil moisture is addressed. For every canopy, soil moisture retrieval is possible. Soil moisture maps are proposed. The canopy temperature can also be retrieved with good accuracy provided both vertical (v) and horizontal (h) polarizations are available. It is shown that the retrieved variables can be used to separate landscape units through a classification procedure.

On the basis of results of simultaneous solution of thermal emission transfer and thermal conductivity equations, the stochastic theory of temperature distribution and thermal radioemission of medium (half-space) has been developed. Expressions for covariance functions of temperature profile and brightness temperature as functions of statistical parameters of half-space surface temperature, which was considered as a random function of time, have been obtained.

Land surface temperature (LST) retrievals obtained from NOAA Advanced Very High Resolution Radiometer (AVHRR) are of considerable importance for climatic research. However, the accurate evaluation of LST from space has been severely limited because of the difficulty in separating atmospheric from surface effects as the surface cannot be modeled as a black-body radiator. With this goal in mind, a novel extension of the split-window technique is presented in which the atmospheric contribution to the radiance measured by the satellite is investigated by the ratioing of covariance and variance of the brightness temperatures measured in Channels 4 and 5 of AVHRR/2. Furthermore, the contribution of emissivity is evaluated from coefficients that depend on the spectral emissivities in both thermal channels. Using a wide range of simulations from an atmospheric radiative transfer model it is shown that the proposed algorithm provides an estimate of LST, to within 0.4 K if the spectral surface emissivity is known, which is better than that given by the currently used split-window algorithms for LST determination. Also the limitations on algorithm accuracy are discussed considering different values of noise equivalent temperature. Finally we present the preliminary results obtained using the proposed method from AVHRR data over a semi-arid region of Northwestern Victoria in Australia provided by CSIRO, and a mountainous region of Northeast of France acquired in the frame of Regio Klimat Projekt.

This paper evaluates the accuracy of three techniques for recovering surface kinetic temperature from multispectral thermal infrared data acquired over land. The three techniques are the reference channel method, the emissivity normalization method, and the alpha emissivity method. The first two methods have been widely used with data from the thermal infrared multispectral scanner (TIMS); the third is a new method. The methods were used to recover the temperature of artificial radiance data derived from a wide variety of materials and convolved with the filter response functions of TIMS and the advanced spaceborne thermal emission reflectance radiometer (ASTER). ASTER is scheduled to fly on the first EOS platform and will have five channels in the thermal infrared with a spatial resolution of 90 m. The results indicate that the emissivity normalization and alpha emissivity techniques are the most accurate, and recover the temperature of the majority of the artificial radiance spectra to within 1.5K; the reference channel method produces less accurate results. The primary advantage of the alpha emissivity method over emissivity normalization method is that it works well in terrains of widely varying emissivities, e.g., those dominated by vegetation and igneous rocks. By contrast, the emissivity normalization method works well only if the emissivity used for normalization is close to the maximum emissivity of the spectra in the scene. The temperature errors for the ASTER convolved data are greater for the emissivity normalization and reference channel methods than for the data convolved to TIMS. The alpha emissivity method is equally accurate for both instruments. In summary, the new alpha emissivity method described herein, should permit more accurate recovery of land surface temperatures from remotely sensed multispectral thermal infrared radiance data, for materials with widely varying and unknown emissivities.

Crystal size of epidotes crystallized in quartz + epidote veins is used as the basis for a new geothermometer from the fossil geothermal field of Saint Martin (Lesser Antilles.) The epidote-bearing alteration paragenesis is developed as far as 3 km from a quartz diorite pluton at temperatures of 220-350 [degrees]C. The length/width ratio of the epidote grains is constant for all the analyzed samples and suggests 'isotropic' growth environments. However, the length and width of the grains vary exponentially with temperature. The obtained results offer new perspectives for simple grain-size geothermometry be must be extended to other geologic environments to clarify the influence of different rock types.

Theory, laboratory experiments, and empirical observation suggest that many aqueous fluid inclusions in calcite reequilibrate during overheating, and therefore some homogenization temperatures ([T.sub.h]) record a temperature close to the maximum reached by the rock. This characteristic suggests that aqueous fluid inclusions in calcite can be used to establish maximum temperature ([T.sub.peak]). To test this hypothesis, we have compiled fluid inclusion [T.sub.h], mean random vitrinite reflectance ([R.sub.m]), and present-day [T.sub.peak] from 46 diverse geologic systems that have been at [T.sub.peak] from [10.sup.4] to [10.sub.6] yr. Present [T.sub.peak] ranged from 65 to 345 [degrees]C, [T.sub.h] modes and means ranged from 59 to 350 [degrees]C, and [R.sub.m] data ranged from 0.4% and 4.6%, spanning the temperature and thermal maturity range associated with burial diagenesis, hydrothermal alteration, and low-grade metamorphism. Plots of [T.sub.h] and [T.sub.peak] data for systems thought to be currently at maximum temperature demonstrate close agreement [T.sub.h] and present [T.sub.peak] in sedimentary basins. Although caution should be applied, the relation suggests that [T.sub.h] of aqueous fluid inclusions in calcite may be a useful measure of maximum temperature. This study also compares [T.sub.h] to mean random vitrinite reflectance ([R.sub.m]) to offer support for the use of [T.sub.h] as a measure of [T.sub.peak], and to provide a better understanding of [R.sub.m]. [T.sub.h] correlates well with [R.sub.m] and results in a curve similar to [R.sub.m] vs. [T.sub.peak] calibrations determined by other workers. The strong correlation (correlation coefficient r = 0.93) between [T.sub.peak] and [R .sub.m] in these systems suggests that maximum temperature is the major control on thermal maturation.

We present an algorithm to retrieve land surface temperatures from wideband thermal infrared measurements using the model of Li et al. [10]. Forward simulation and inversion demonstrates the method to be stable in the presence of observation noise. Results from inversions performed using field measurements show that errors are generally less than the uncertainty in the observations. Index Terms--Directional effects, inversion, land surface temperature, noise, wide band.

The land skin temperature, an important feature for agricultural monitoring, convective processes, and the earth's radiation budget, is monitored from limited-view satellite imagers. The angular dependence of this parameter is examined using simultaneous views of clear areas from up to three geostationary satellites. Daytime temperatures from different satellites differed by up to 6 K and varied as a function of the time of day. Larger differences are expected to occur but were not measured because of limited viewing angles. These differences suggest that biases may occur in both the magnitude and phase of the diurnal cycle of skin temperature and its mean value whenever geostationary satellite data are used to determine skin temperature. The temperature differences were found over both fiat and mountainous regions with some slight dependence on vegetation. The timing and magnitude of the temperature differences provide some initial validation for relatively complex model calculations of skin temperature variability. The temperature differences are strongly correlated with terrain and the anisotropy of reflected solar radiation for typical land surfaces. These strong dependencies suggest the possibility for the development of a simple empirical approach for characterizing the temperature anisotropy. Additional research using a much greater range of viewing angles is required to confirm the potential of the suggested empirical approach.

April's combined land and sea surface temperature: the hottest April on record, at 0.76[degrees]C above the average for the twentieth century. Source: [...]

Temperatures at the Earth's core-mantle boundary (CMB) may be far lower than previously thought. R. Boehler and colleagues in Germany used a laser-heated diamond-anvil cell to find the melting points of three probable components of the core: Fe, FeO and FeS. The results indicated that the CMB's minimum temperature is between 2,600 and 3,400 K. This is significantly lower than the 3,600 to 5,300 K estimate obtained earlier by R. Jeanloz and colleagues in the US. The lower temperatures may force a re-examination of current ideas on the Earth's heat budget and generation of the magnetic dipole.

The author explains the different reasons that caused a sudden drop in the temperature of the Earth's surface in the mid-twentieth century, the post-industrial warming period. It is shown that a change in the technique used for measuring the temperatures above the ocean led and not the climate itself led to the observed changes.